1. Technical Field
The disclosed embodiments relate generally to a switch mode power converter, and more specifically, to a switch mode power converter that facilitates communication from a load device coupled to a secondary side of the power supply to a primary side controller.
2. Description of the Related Arts
In a conventional isolated switching power supply such as a flyback power converter, a switch controller located on the primary side of the power supply regulates power to the load by controlling on-times and off-times of a switch based upon one or more feedback signals representing output power, output voltage, and/or output current. It is often desirable to communicate messages from the load device to the primary side controller so that the load device can communicate a desired voltage, current, or operating mode to be provided by the power converter. In devices that distribute power through a standard Universal Serial Bus (USB) cable, there are different conventional methods of communication. Some conventional systems rely on communication through the D+/D− data lines of USB during negotiation stages where the power delivery method can be changed to different modes. However, it is often undesirable to use the D+/D− lines because connecting these lines to anything other than their normal high-speed communication path may impact the bit error rate. Another disadvantage of communicating operating mode information using the D+/D− data lines is that it such solutions typically require a communication integrated circuit on the secondary side of the charger/adapter, thereby increasing overall cost of the system.